Typically LCs are aligned by rubbed polymer films. The rubbing imparts an orientation to the film, which is then transferred to the LC sample when the LC is placed in contact with the treated surface. Alignment has also been achieved using a protocol where the glass plates are treated with a solution of molecules of the general structure Cl.sub.3 SiR.sup.1 or (R.sup.2 O).sub.3 SiR.sup.1, where R.sup.1 can be an alkyl group or, for example, a mesogenic structure, and R.sup.a is a methyl or ethyl group. This results in a surface covered with a very thin polymeric film of the polysiloxane type where some of the silicones are covalently attached to the glass substrate. Typically, these surfaces are not well characterized before being used for LC alignment.
However, it is known that extremely high quality polysiloxane monolayers on glass, or alkylthiols on gold, can be obtained (see for example: L. Netzer and J. Sagiv, J. Am. Chem. Soc., 105, 674-676 (1983). These self-assembled monolayers (SAMs) result when polymer precursor molecules assemble on the surface prior to polymerization to form a "perfect" monolayer, then polymerize from this self-assembled pre-polymer. Often, very similar protocols lead to qualitatively different surfaces. A true self-assembled monolayer should afford complete coverage and give a surface which, when formed on very smooth "float glass" is just as smooth as the glass substrate. The quality of the SAM can be tested by atomic force microscopy. A poor surface will exhibit features on the order of tens of .ANG., with pits. A true SAM will exhibit an atomic force microscope scan indistinguishable from a smooth float glass surface. In addition, while glass wets with water, the poor treated surface will exhibit some wetability, and the true SAM will not wet at all. True SAMs can also be characterized by other techniques, such as atom scattering, and SAMs on other substrates, such as silicon, can be characterized by techniques such as ellipsometry and IR spectroscopy.